Subject-matching in images is the process of determining whether individuals in separate images are the same person. This matching is based on the visual similarity of the individual in each image, along with any knowledge of the time or location at which the images are taken. Generally, an individual depicted in a target image, sometimes taken from a video sequence, is compared with a source image, or training set, of possible matching images, to find the most similar match.
Visual information, also known as visual features, may be used for the comparison. For example, color features collected over horizontal stripes in the target sequence images may be compared with the same horizontal stripes in the source sequence images. Such features are relatively robust to changes in orientation of the subject, because the color of a subject is typically fairly constant along a horizontal axis.
However, there is a need to improve the accuracy of subject-matching for a wider range of possible situations.